Commit 6f91d31d authored by Quentin Perret's avatar Quentin Perret Committed by Marc Zyngier
Browse files

KVM: arm64: Drop pkvm_mem_transition for host/hyp donations 



Simplify the __pkvm_host_donate_hyp() and pkvm_hyp_donate_host() paths
by not using the pkvm_mem_transition machinery. As the last users of
this, also remove all the now unused code.

No functional changes intended.

Signed-off-by: default avatarQuentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20250110121936.1559655-4-qperret@google.com


Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent 7cbf7c37

arch/arm64/kvm/hyp/nvhe/mem_protect.c

+32 −253
Original line number Diff line number Diff line
@@ -583,39 +583,6 @@ void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt) 
	BUG_ON(ret && ret != -EAGAIN);

}



struct pkvm_mem_transition {

	u64				nr_pages;



	struct {

		enum pkvm_component_id	id;

		/* Address in the initiator's address space */

		u64			addr;



		union {

			struct {

				/* Address in the completer's address space */

				u64	completer_addr;

			} host;

			struct {

				u64	completer_addr;

			} hyp;

		};

	} initiator;



	struct {

		enum pkvm_component_id	id;

	} completer;

};



struct pkvm_mem_share {

	const struct pkvm_mem_transition	tx;

	const enum kvm_pgtable_prot		completer_prot;

};



struct pkvm_mem_donation {

	const struct pkvm_mem_transition	tx;

};



struct check_walk_data {

	enum pkvm_page_state	desired;

	enum pkvm_page_state	(*get_page_state)(kvm_pte_t pte, u64 addr);
@@ -675,56 +642,6 @@ static int __host_set_page_state_range(u64 addr, u64 size, 
	return 0;

}



static int host_request_owned_transition(u64 *completer_addr,

					 const struct pkvm_mem_transition *tx)

{

	u64 size = tx->nr_pages * PAGE_SIZE;

	u64 addr = tx->initiator.addr;



	*completer_addr = tx->initiator.host.completer_addr;

	return __host_check_page_state_range(addr, size, PKVM_PAGE_OWNED);

}



static int host_initiate_donation(u64 *completer_addr,

				  const struct pkvm_mem_transition *tx)

{

	u8 owner_id = tx->completer.id;

	u64 size = tx->nr_pages * PAGE_SIZE;



	*completer_addr = tx->initiator.host.completer_addr;

	return host_stage2_set_owner_locked(tx->initiator.addr, size, owner_id);

}



static bool __host_ack_skip_pgtable_check(const struct pkvm_mem_transition *tx)

{

	return !(IS_ENABLED(CONFIG_NVHE_EL2_DEBUG) ||

		 tx->initiator.id != PKVM_ID_HYP);

}



static int __host_ack_transition(u64 addr, const struct pkvm_mem_transition *tx,

				 enum pkvm_page_state state)

{

	u64 size = tx->nr_pages * PAGE_SIZE;



	if (__host_ack_skip_pgtable_check(tx))

		return 0;



	return __host_check_page_state_range(addr, size, state);

}



static int host_ack_donation(u64 addr, const struct pkvm_mem_transition *tx)

{

	return __host_ack_transition(addr, tx, PKVM_NOPAGE);

}



static int host_complete_donation(u64 addr, const struct pkvm_mem_transition *tx)

{

	u64 size = tx->nr_pages * PAGE_SIZE;

	u8 host_id = tx->completer.id;



	return host_stage2_set_owner_locked(addr, size, host_id);

}



static enum pkvm_page_state hyp_get_page_state(kvm_pte_t pte, u64 addr)

{

	if (!kvm_pte_valid(pte))
@@ -745,52 +662,6 @@ static int __hyp_check_page_state_range(u64 addr, u64 size, 
	return check_page_state_range(&pkvm_pgtable, addr, size, &d);

}



static int hyp_request_donation(u64 *completer_addr,

				const struct pkvm_mem_transition *tx)

{

	u64 size = tx->nr_pages * PAGE_SIZE;

	u64 addr = tx->initiator.addr;



	*completer_addr = tx->initiator.hyp.completer_addr;

	return __hyp_check_page_state_range(addr, size, PKVM_PAGE_OWNED);

}



static int hyp_initiate_donation(u64 *completer_addr,

				 const struct pkvm_mem_transition *tx)

{

	u64 size = tx->nr_pages * PAGE_SIZE;

	int ret;



	*completer_addr = tx->initiator.hyp.completer_addr;

	ret = kvm_pgtable_hyp_unmap(&pkvm_pgtable, tx->initiator.addr, size);

	return (ret != size) ? -EFAULT : 0;

}



static bool __hyp_ack_skip_pgtable_check(const struct pkvm_mem_transition *tx)

{

	return !(IS_ENABLED(CONFIG_NVHE_EL2_DEBUG) ||

		 tx->initiator.id != PKVM_ID_HOST);

}



static int hyp_ack_donation(u64 addr, const struct pkvm_mem_transition *tx)

{

	u64 size = tx->nr_pages * PAGE_SIZE;



	if (__hyp_ack_skip_pgtable_check(tx))

		return 0;



	return __hyp_check_page_state_range(addr, size, PKVM_NOPAGE);

}



static int hyp_complete_donation(u64 addr,

				 const struct pkvm_mem_transition *tx)

{

	void *start = (void *)addr, *end = start + (tx->nr_pages * PAGE_SIZE);

	enum kvm_pgtable_prot prot = pkvm_mkstate(PAGE_HYP, PKVM_PAGE_OWNED);



	return pkvm_create_mappings_locked(start, end, prot);

}



static enum pkvm_page_state guest_get_page_state(kvm_pte_t pte, u64 addr)

{

	if (!kvm_pte_valid(pte))
@@ -812,94 +683,6 @@ static int __guest_check_page_state_range(struct pkvm_hyp_vcpu *vcpu, u64 addr, 
	return check_page_state_range(&vm->pgt, addr, size, &d);

}



static int check_donation(struct pkvm_mem_donation *donation)

{

	const struct pkvm_mem_transition *tx = &donation->tx;

	u64 completer_addr;

	int ret;



	switch (tx->initiator.id) {

	case PKVM_ID_HOST:

		ret = host_request_owned_transition(&completer_addr, tx);

		break;

	case PKVM_ID_HYP:

		ret = hyp_request_donation(&completer_addr, tx);

		break;

	default:

		ret = -EINVAL;

	}



	if (ret)

		return ret;



	switch (tx->completer.id) {

	case PKVM_ID_HOST:

		ret = host_ack_donation(completer_addr, tx);

		break;

	case PKVM_ID_HYP:

		ret = hyp_ack_donation(completer_addr, tx);

		break;

	default:

		ret = -EINVAL;

	}



	return ret;

}



static int __do_donate(struct pkvm_mem_donation *donation)

{

	const struct pkvm_mem_transition *tx = &donation->tx;

	u64 completer_addr;

	int ret;



	switch (tx->initiator.id) {

	case PKVM_ID_HOST:

		ret = host_initiate_donation(&completer_addr, tx);

		break;

	case PKVM_ID_HYP:

		ret = hyp_initiate_donation(&completer_addr, tx);

		break;

	default:

		ret = -EINVAL;

	}



	if (ret)

		return ret;



	switch (tx->completer.id) {

	case PKVM_ID_HOST:

		ret = host_complete_donation(completer_addr, tx);

		break;

	case PKVM_ID_HYP:

		ret = hyp_complete_donation(completer_addr, tx);

		break;

	default:

		ret = -EINVAL;

	}



	return ret;

}



/*

 * do_donate():

 *

 * The page owner transfers ownership to another component, losing access

 * as a consequence.

 *

 * Initiator: OWNED	=> NOPAGE

 * Completer: NOPAGE	=> OWNED

 */

static int do_donate(struct pkvm_mem_donation *donation)

{

	int ret;



	ret = check_donation(donation);

	if (ret)

		return ret;



	return WARN_ON(__do_donate(donation));

}



int __pkvm_host_share_hyp(u64 pfn)

{

	u64 phys = hyp_pfn_to_phys(pfn);
@@ -964,30 +747,29 @@ int __pkvm_host_unshare_hyp(u64 pfn) 


int __pkvm_host_donate_hyp(u64 pfn, u64 nr_pages)

{

	u64 phys = hyp_pfn_to_phys(pfn);

	u64 size = PAGE_SIZE * nr_pages;

	void *virt = __hyp_va(phys);

	enum kvm_pgtable_prot prot;

	int ret;

	u64 host_addr = hyp_pfn_to_phys(pfn);

	u64 hyp_addr = (u64)__hyp_va(host_addr);

	struct pkvm_mem_donation donation = {

		.tx	= {

			.nr_pages	= nr_pages,

			.initiator	= {

				.id	= PKVM_ID_HOST,

				.addr	= host_addr,

				.host	= {

					.completer_addr = hyp_addr,

				},

			},

			.completer	= {

				.id	= PKVM_ID_HYP,

			},

		},

	};



	host_lock_component();

	hyp_lock_component();



	ret = do_donate(&donation);

	ret = __host_check_page_state_range(phys, size, PKVM_PAGE_OWNED);

	if (ret)

		goto unlock;

	if (IS_ENABLED(CONFIG_NVHE_EL2_DEBUG)) {

		ret = __hyp_check_page_state_range((u64)virt, size, PKVM_NOPAGE);

		if (ret)

			goto unlock;

	}



	prot = pkvm_mkstate(PAGE_HYP, PKVM_PAGE_OWNED);

	WARN_ON(pkvm_create_mappings_locked(virt, virt + size, prot));

	WARN_ON(host_stage2_set_owner_locked(phys, size, PKVM_ID_HYP));



unlock:

	hyp_unlock_component();

	host_unlock_component();
@@ -996,30 +778,27 @@ int __pkvm_host_donate_hyp(u64 pfn, u64 nr_pages) 


int __pkvm_hyp_donate_host(u64 pfn, u64 nr_pages)

{

	u64 phys = hyp_pfn_to_phys(pfn);

	u64 size = PAGE_SIZE * nr_pages;

	u64 virt = (u64)__hyp_va(phys);

	int ret;

	u64 host_addr = hyp_pfn_to_phys(pfn);

	u64 hyp_addr = (u64)__hyp_va(host_addr);

	struct pkvm_mem_donation donation = {

		.tx	= {

			.nr_pages	= nr_pages,

			.initiator	= {

				.id	= PKVM_ID_HYP,

				.addr	= hyp_addr,

				.hyp	= {

					.completer_addr = host_addr,

				},

			},

			.completer	= {

				.id	= PKVM_ID_HOST,

			},

		},

	};



	host_lock_component();

	hyp_lock_component();



	ret = do_donate(&donation);

	ret = __hyp_check_page_state_range(virt, size, PKVM_PAGE_OWNED);

	if (ret)

		goto unlock;

	if (IS_ENABLED(CONFIG_NVHE_EL2_DEBUG)) {

		ret = __host_check_page_state_range(phys, size, PKVM_NOPAGE);

		if (ret)

			goto unlock;

	}



	WARN_ON(kvm_pgtable_hyp_unmap(&pkvm_pgtable, virt, size) != size);

	WARN_ON(host_stage2_set_owner_locked(phys, size, PKVM_ID_HOST));



unlock:

	hyp_unlock_component();

	host_unlock_component();